Released digitally last Monday (May 3) just four days after its radio premiere, "Not Afraid" busts out of the gate with 380,000 first-week digital downloads[3], according to Nielsen SoundScan -- the biggest sales week for a digital track this calendar year. The song also debuts at No. 24 on the radio-based Rap Songs chart, and is bubbling under the Radio Songs chart with 10.3 million listener impressions, according to Nielsen BDS.

"Not Afraid" is the lead single from Eminem's new album "Recovery," due out on June 22. The single is the first to debut at No. 1 on the Billboard Hot 100 since Oct. 17, 2009, when Britney Spears[5]' "3" danced in at No. 1. "Afraid" is only the second rap single to start at No. 1 following "I'll Be Missing You" by Puff Daddy & Faith Evans featuring 112, which began its 11-week run at the summit on the chart dated June 14, 1997.

"Not Afraid" is Eminem's third chart-topper. He first led the list for 12 weeks with "Lose Yourself" in 2002-03 and made an impressive 78-1 jump with "Crack A Bottle," along with Dr. Dre[6] and 50 Cent[7], on the list dated Feb. 21, 2009. "Bottle" set a then-record for selling the most downloads in its first week of release (418,000), a mark shattered the following week when Flo Rida[8]'s "Right Round" started with 636,000.

Of the 16 debuts at No. 1, a full 10 of them came between 1995 and 1998. Until the end of 1998, a song could only chart on the Hot 100 if it was released as a commercially available single. The bevy of debuts was prompted by singles being withheld from the market in order to maximize chart position on the tally -- which is based on combining airplay with sales information. At the end of 1998, the Hot 100 changed its formula, allowing airplay-only, or non-commercially available songs to chart.

Thus, it's much harder now for a single to enter at No. 1, as radio airplay will usually enable a song to debut at lower rank. But as Spears and Eminem have proven, instant reaction with a huge sales number can trigger a perfect storm and prompt a No. 1 entry right out of the gate.